Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!utgpu!water!watnot!watmath!clyde!rutgers!husc6!linus!philabs!ttidca!hollombe From: hollombe@ttidca.UUCP Newsgroups: sci.crypt,comp.sys.ibm.pc,comp.sources.wanted Subject: Re: Need information on data compression algorithms Message-ID: <635@ttidca.UUCP> Date: Thu, 9-Apr-87 20:05:38 EST Article-I.D.: ttidca.635 Posted: Thu Apr 9 20:05:38 1987 Date-Received: Sat, 11-Apr-87 21:05:10 EST References: <528@savax.UUCP> Reply-To: hollombe@ttidcb.UUCP (The Polymath) Organization: The Cat Factory Lines: 31 Xref: utgpu sci.crypt:299 comp.sys.ibm.pc:2853 comp.sources.wanted:868 >> Once apon a time, about five years ago, a UK company called DJAI, (the >> authors of The Last One - a 4GL program generator) said that they had an >> algorithm which would (reversibly) compress arbitrary text into 40-80 bytes. >> They even had a demonstration system which claimed to show the algorithm in >> operation. >> >> They planned to demonstrate the system by compressing the complete source >> text of The Last One, copying the <80 bytes to a hand-held micro with a >> printer, then decompressing and producing the total listing from the micro. > Anyone know -anything- (or have any guesses) about the algorithm? There are algorithms that can do this, though whether they could be implemented on a micro is problematical. The one that comes to mind is converting the arbitrary text into one _very_ large number and then representing that number as a combination of powers of smaller numbers. E.g.: 1234^5678 + 456^123 + 90^20 - 8^2 - 3 Note the above amount probably couldn't be contained in the known universe if you attempted to write it out in full, but the above representation is highly compact. Sorry, I'm not aware of the details of how the text conversion and restoration is done. I think Kurt Goedel (as in _Goedel, Escher, Bach: an Eternal Golden Braid_) first proposed the technique (occasionally referred to as "Goedelizing"). -- The Polymath (aka: Jerry Hollombe, hollombe@TTI.COM) Citicorp(+)TTI 3100 Ocean Park Blvd. (213) 450-9111, x2483 Santa Monica, CA 90405 {csun|philabs|psivax|trwrb}!ttidca!hollombe